Corrêa Isadora Alonso, de Souza Marcos Romário Matos, da Silva Gustavo Peixoto Duarte, Pimentel Anna Beatriz Sampaio Vianna Macedo, Calil Pedro Telles, Cunha Marcela Sabino, Mariani Diana, Brindeiro Rodrigo de Moraes, Costa Sara Mesquita, Simas Maria Clara da Costa, Ota Victor Akira, Pereira Elisa Cavalcante, Siqueira Marilda Mendonça, Resende Paola Cristina, Galliez Rafael Mello, Faffe Debora Souza, Silva Rosane, Castiñeiras Terezinha Marta Pereira Pinto, Tanuri Amilcar, da Costa Luciana Jesus
Laboratório de Genética e Imunologia das Infecções Virais, Departamento de Virologia, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.
Laboratório de Virologia Molecular, Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.
Front Cell Infect Microbiol. 2025 Jul 11;15:1582137. doi: 10.3389/fcimb.2025.1582137. eCollection 2025.
The COVID-19 pandemic was characterized by the sequential introduction and circulation of distinct SARS-CoV-2 variants, which presented differences in transmission capacity and pathogenicity. However, the relationship between these differences and the replicative capacity of these variants remains to be determined. Our research aimed to compare the biological traits of the SARS-CoV-2 lineages B.1.1.33, and variants Zeta (P.2), Gamma (P.1/P.1.), Delta (B.1.617.2/AY.), and Omicron (BA.1).
We employed three different cellular models susceptible to viral infection to demonstrated the differences in virus binding, entry and total RNA production through RT-qPCR assay and viral infectious progeny by plaque assay. The RNA replication was evaluated by dsRNA immunofluorescence and the viral protein production by western blotting analysis. NGS and RT-qPCR analysis were also used in competition experiments to verify the viral variants dynamic in cell culture.
We found that the differences in viral replication varied according to the cell type, with Omicron BA.1 exhibiting the lowest replication capacity in human pulmonary cells. Additionally, we demonstrated the occurrence of nucleocapsid proteoforms generated during infection and differences in size and number of sites of viral RNA replication for each virus.
These data suggest that factors beyond the initial stages of virus entry influence the efficiency of viral replication among different SARS-CoV-2 variants. Thus, our study underscores the significance of RNA replication and the role of nucleocapsid proteins in shaping the replicative characteristics of SARS-CoV-2 variants.
新冠疫情的特点是不同的严重急性呼吸综合征冠状病毒2（SARS-CoV-2）变体相继出现并传播，这些变体在传播能力和致病性方面存在差异。然而，这些差异与这些变体的复制能力之间的关系仍有待确定。我们的研究旨在比较SARS-CoV-2谱系B.1.1.33以及变体泽塔（P.2）、伽马（P.1/P.1.）、德尔塔（B.1.617.2/AY.）和奥密克戎（BA.1）的生物学特性。
我们采用了三种易受病毒感染的不同细胞模型，通过逆转录定量聚合酶链反应（RT-qPCR）测定法来证明病毒结合、进入和总RNA产生的差异，并通过噬斑测定法来检测病毒感染性后代。通过双链RNA免疫荧光评估RNA复制，通过蛋白质免疫印迹分析评估病毒蛋白产生。在竞争实验中还使用了二代测序（NGS）和RT-qPCR分析，以验证细胞培养中病毒变体的动态变化。
我们发现病毒复制的差异因细胞类型而异，奥密克戎BA.1在人肺细胞中的复制能力最低。此外，我们证明了感染期间产生的核衣壳蛋白变体的存在，以及每种病毒在病毒RNA复制位点的大小和数量上的差异。
这些数据表明，病毒进入初始阶段之外的因素会影响不同SARS-CoV-2变体之间的病毒复制效率。因此，我们的研究强调了RNA复制的重要性以及核衣壳蛋白在塑造SARS-CoV-2变体复制特征中的作用。
